Capacitive sensing system and wash/alignment station for a chemical analyzer

A probe alignment apparatus for a chemical analyzer, comprising:

• a fixed framework;
• an alignment station fixed to the framework;
• a vertical pipette having an electrically-conductive exterior and an open lower end;
• probe arm means operably supporting the pipette on the framework for positioning its lower end above the alignment station;
• and
• an electrically conductive plate positioned at the alignment station in the path of the pipette, the plate having an alignment measuring edge arranged adjacent an intended path of the pipette;
• operator means for moving the pipette relative to the alignment measuring edge during an alignment test;
• and
• probe detector means for generating a signal when the pipette contacts the alignment measuring edge to indicate that the pipette is not properly positioned relative to the fixed framework.

A pipette wash/alignment apparatus for a chemical analyzer including a wash/alignment station, comprising:

• an upright electrically conductive pipette having a tip leading to an open lower end;
• probe arm means operably supporting the pipette for positioning its lower end above the wash/alignment station and for subsequently moving it relative to the wash/alignment station;
• a pressurized source of wash liquid operably connected to the pipette for selectively discharging the wash liquid from its lower end;
• wash well means located at the wash/alignment station for receiving a lower portion of the pipette;
• probe detection means including a conductive plate arranged across the wash well for monitoring the position of the pipette;
• and
• oscillator means for applying an oscillating voltage to the conductive plate.